final exam ta review Flashcards
1
Q
Nucleotides
A
Building blocks of DNA
2
Q
Base Pairs in DNA
A
A-T
C-G
3
Q
Base pairs in RNA
A
A-U
C-G
4
Q
Allele
A
An alternative form of a specific gene
5
Q
Traits
A
Characteristics of an organism
Ex: pea plant color, height, color of seed, ect.
6
Q
Homologs
A
One of the chromosomes in a pair of homologous chromosomes
7
Q
Haploid
A
Refers to an organism of cells that contain 1 set of chromosomes
Humans this is our gametic cells
8
Q
Diploid
A
Refers to an organism or cell that contain 2 sets of chromosomes
In humans this is our somatic cells
9
Q
Plant genome from seed to seedless
A
Diploids have seed
Tripod don’t have seeds
10
Q
Sister Chromatids
A
Unit of a two identical chromatids and a centromere
11
Q
Homologous chromosomes
A
Pair of chromosomes, one of which is from your mother, and the other is from your father
12
Q
Homozygous
A
Same allele for a trait
13
Q
Heterozygous
A
Two different alleles for a trait
14
Q
Dominant
A
AA or Aa
15
Q
Recessive
A
aa
16
Q
Dosage compensation
A
Refers to the phenomena in which levels of expression of many genes on the sex chromosome is similar in both sexes even though males and females have different sex chromosomes
16
Q
Genetic Variation
A
The differences in inherited traits within a population
16
Q
Mendelian ratios
A
Single trait ratios
Aa x Aa
25% AA, 50% Aa, 25% aa
Genotypic ratio: 1:2:1
Phenotypic ratio: 3:1
Two Trait Ratios
AaBb x AaBb
Phenotypic Ratio : 9:3:3:1
17
Q
Mendel’s law of independent assortment
A
Two different genes randomly assort their alleles during the process that gives rise to gametes
18
Q
Barr bodies
A
A structure in the interphase nuclei of somatic cell of female mammals that is a highly condensed X- chromosomes
XX (has one barr body)
XY (has no barr body)
XXY(has one barr body)
XXX (has two barr bodies)
19
Q
Z-W system
A
Bird sex determination
ZZ = male (homogametic)
ZW= female (Heterogameitc)
20
Q
Incomplete penetrance
A
This pattern occurs when dominant phenotype is not expressed even though an individual carries a dominant allele.
Ex: individual who carries the polydactyly allele (dominant allele) but has normal # of fingers
21
Q
Incomplete dominance
A
This pattern occurs when the heterozygote has a phenotype that is the intermediate between the corresponding homozygotes
Red= AA, White= aa, Pink = Aa
22
Q
Codominance
A
Inheritance pattern occur when the heterozygote expresses both alleles simultaneously without forming an intermediate phenotype
Ex: AB blood type
23
Overdominance
When the heterozygote has a greater level of reproductive success than either homozygote
Ex: Sickle cell anemia
24
Nondisjunction
Failure of chromosomes to separate correctly during anaphase
25
Trisomy
Contains an extra chromosome (2n +1)
Ex: trisomy 21
26
Nonessential genes
Not required for survival although likely beneficial
27
Essential genes
Genes that encodes for a protein that is considered necessary for survival
28
Lethal alleles
An allele that has the potential to cause death
29
Endosymbiosis
Describes a symbiotic relationship in which the symbiotic usually lives in the host
EX: mitochondria and chloroplasts
30
Gene Imprinting
Refers to a pattern of inheritance that involves a change in a single gene or chromosome during gamete formation.
Typically done by methylation
31
Maternal Effect
An inheritance pattern of certain nuclear genes in which the genotype of mother directly determines the phenotype of her offspring
32
Snail coiling (maternal effect)
Based off of mother genotype
33
Recombinant chromosomes
Refers to the combination of alleles or traits that are different than parents
Is a result of crossing over
34
Genetic Linkage
Is the phenomenon in which genes that are close together on the same chromosome tend to be transmitted as a unit
35
Autosomal linkage groups
All the homologous chromosomes paired up that are autosomal (22 chromosomes in humans)
EX: Chromosome 1 paired with chromosomes 1, Chromosomes 2 paired up with chromosome 2
36
What is the hardy-weinberg equation?
p2+ 2pq + q2 = 1
p2 = AA
2pq = Aa
q2 = aa
37
Natural selection
The process by which differential fitness acts on the gene pool. When a mutation creates a new allele that is beneficial, the allele may become prevalent within the future generations, because the individuals with the allele will have greater reproductive success and survival.
38
Genetic Drift
mechanism of evolution occurs when allele frequencies change over generations due to random chance
39
Translocation
When one segment of a chromosomes becomes attached to a different part of the same chromosome
Can be an issue if important gene that are euchromatin get translocated to section of heterochromatin (this would turn off the important genes)
40
Terminal deletion
Loss of a segment from the end of the linear chromosome
41
Interstitial deletion
Loss of an internal segment from a linear chromosome
42
Paracentric inversion
Centromere lies outside of the inverted region
43
Pericentric inversion
Centromere lies within the inverted region of the chromosome
44
Concordance values
For Siblings
0.5
Identical Twins
1.0
Parent of Offspring
0.5
Aunt/Uncle to Offspring
0.25
Grandparent to Offspring
0.25
45
Transduction
A virus infects a bacterium and then transfers genetic material to bacteria
46
Conjugation
Involves a direct physical interaction between two bacterial cells one bacterium to another
47
Transformation
Is a process in which genetic material is released into the environment when a bacterial cell dies. This dead bacterial genetic material can then be taken up into the cell
48
Hfr
Has fertility factor plasmid completely integrated into the host genome and can NOT form a sex pilus
48
F+
Has a fertility plasmid not integrated into the host genome and can from a sex pilus
49
F’
Has fertility plasmid partially integrated into the host genome and rarely from a sex pilus
50
Prophage
Bacteriophage that integrates genetic material with the host genetic material
51
Temperate phage
A bacteriophage that has both lytic and lysogenic cycles as a means of reproduction
51
Virulent phage
A bacteriophage that only has a lytic cycle as a means of reproduction
52
Lytic cycle
a viral reproductive cycle in which copies of a virus are made within a host cell, which then bursts open, releasing new viruses.
53
Lysogenic cycle
a viral reproductive stage where the virus's DNA is replicated using the host cell's DNA
Typically integrated and remains so until advantageous time like when the body is immunosuppressed
54
Episome
A segment of DNA such as a plasmid that can replicate independently of the chromosomal DNA and can also integrate into the chromosome
55
Reverse transcriptase
Used to convert RNA to DNA
Used in viral integration like in HIV or in retrotransposition
55
Transcription
Conversion of DNA to RNA
Can occur simultaneously with Translation in prokaryotes (not eukaryotes)
56
HIV
RNA virus
RNA virus gets converted to DNA using reverse transcriptase, then gets integrated into the host cell using integrase enzyme
Virus prone to many mutation which makes it very hard to treat due to it being an RNA virus
57
Translation
Conversion of RNA to protein
Can occur simultaneously with transcription in prokaryotes (not eukaryotes)
57
Conservative theory of DNA
After one round of replication, half of the new DNA double helices would be composed of completely old, or original, DNA, and the other half would be completely new.
58
Semiconservative theory of DNA
After one round of replication, every new DNA double helix would be a hybrid that consisted of one strand of old DNA bound to one strand of newly synthesized DNA.
59
Dispersive theory of DNA
the original DNA double helix breaks apart into fragments, and each fragment then serves as a template for a new DNA fragment
60
Retrotransposition
A transposable element that moves via transposition → transcribed into RNA then reverse transcriptase makes a second copy in DNA
61
Levels of chromosome compaction
Nucleosomes (first level)
30 fibers (second level)
Loop domains (third level)
Metaphase chromosomes (fourth level)
62
Helicase
Unzips the DNA
63
Toposiomerase
(aka DNA gyrase) Relaxes supercoiling ahead of the replication fork
64
DNA polymerase III
Synthesizes the DNA in the leading and lagging strands
65
Double stranded binding proteins
Holds up the double stranded DNA to from the replication fork (makes sure that the DNA being duplicated does not rejoin during the duplication process
65
DNA Ligase
Glues together the okazaki fragments
66
Directionality and orientation of DNA
Always goes in the 5’ to 3’ direction when being synthesized
Is in the Antisense confirmation
67
Complementary DNA
5’ ATCGATCG 3’ is complementary to 3’ TAGCTAGC 5’
68
Introns
Non-coding sequences present in mRNA→do not lead to any protein production
69
Exons
Functional or coding sequences present in mRNA→leads to protein production (gene expression)
69
Alternative splicing
The phenomenon that a pre-mRNA can be spliced in more than one way
Allows you to make more than one gene product (protein) with just one gene
70
mRNA modifications
5 prime cap
Poly A tail
71
tRNA
RNA molecule that carries the amino acids that correspond to codons in the mRNA. A tRNA molecule has an anticodon to pair with specific trinucleotide sequences
72
Shine-Dalgarno sequence
Ribosomal-binding site that facilitates the binding of mRNA to the 30S subunit
73
Kozak sequence
Like the Shine-Dalgarno sequence but for eukaryotes
74
Genetic testing
Genetic testing is for individuals looking to see if there is a genetic abnormality
74
Mutation
A change in DNA sequence and must be inheritable
75
Genetic screening
Genetic testing for a population wide basis for genetic abnormality
76
Amniocentesis
A type of genetic testing (individual) where amniotic fluid is sampled to look at fetal genetic abnormalities
76
Environmental mutagens
Mutagens outside the body
Include UV rays, Gamma rays, and X-rays
76
CpG islands
Clusters of C(ytosine) and G(uanine), associated with epigenetics via methylation of Cytosines
77
Constitutive
Means to be expressed continuously at constant levels of expression
78
Repressor proteins
Proteins used in negative feedback loops
repress/prevent the transcription of certain genes
79
Tumor suppressor genes
Inhibit cell growth and division
Protect us from cancer
80
Oncogenes
Promote cell growth and division
Result in cancer
81
Beneficial mutation
Mutations that a good for an organism 🙂
Typically leads to better reproductive success
82
Conditional mutation
Mutations that depend on the environment like temperature
83
Deleterious mutation
Mutations that are not good, and can be detrimental to the organism
84
Silent mutation
Mutation in which the codon for an amino acid gets changed, but due to the degenerate nature of codons still codes for the same amino acid
85
Euchromatin
Less condensed regions of chromosomes, transcriptionally active
86
Heterochromatin
Tightly compacted regions of chromosomes, generally transcriptionally inactive
87
Antisense RNA
An RNA strand that is complementary to mRNA (creates double stranded RNA which prevents translation
88
Mutagens
An agent that causes alerternations in the structure of DNA
89
Methylation of Histones
Makes the DNA associate more with the histones (DNA is now more tight around the histones)
Creates closed chromatin conformation
90
Acetylation of Histones
Makes the DNA associate less with the histones (DNA is now less tight around the histones)
Creates open chromatin conformation
91
Activators
Proteins that bind to enhancer regions
92
Enhancers
Regions where activators bind
93
Repressors
Proteins that bind to silencing regions
94
Silencers
Regions where repressors bind
